Healthy elderly people aged 70 or more should receive a starting dosage of the anxiolytic drug suriclone half that recommended for younger people; frail or ill elderly people may require further dosage reduction. These conclusions were based on a study of the pharmacokinetics and tolerability of orally administered suriclone after a single dose of 0.2mg and after multiple doses of 0.2mg 3-times daily in 8 male and 8 female healthy elderly volunteers. Informal comparisons of the pharmacokinetic data from this study with studies in younger volunteers showed a 53% decrease in clearance and an 84% increase in elimination half-life. Area under the plasma concentration-time curve (AUC) for suriclone and total antigenic products in the elderly were twice the values in younger volunteers when adjusted for different dosage. There were no significant changes in pulse rate or blood pressure during the study. One person showed a change from sinus rhythm to atrial fibrillation. Six people had transient adverse events including unsteadiness, vomiting, difficulty in reaching for objects, urinary incontinence and sedation.